<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
    </ul>
</div>
</body>
<style>
    ul{
        display:flex;
        display:-webkit-flex;
        flex-wrap:wrap;
    }
    li{
        width:30%;
    }
</style>
</html>